Not necessary for professional school applications. You should have better motives than beefing up your medical school app if you are going to put yourself through so much extra work. The double major only increases your application competitiveness marginally if at all.
I would pick the major that interests you the most, take the pre-reqs you need for medical school and to prepare you for the MCAT and be happy with that. But some people are studyaholics so whatever floats your boat I guess.
Enjoying your freshman year of college should be your main focus. As long as you are still making A's and not doing anything criminal then I would highly encourage you to spend plenty of time goofing off. Utilize to the fullest the time window you have before you actually need to start having real consternation over pre-med things. 😉